A. Field of the Invention
The applicant's invention relates to a device which allows an occupant of a wheelchair to operate the wheelchair by propelling himself with one arm, more particularly it relates to a device which can be attached to any wheelchair and which allows the occupant of the wheelchair to operate the wheelchair by propelling himself with one arm and even more particularly it relates to a device which can be attached to any wheelchair and which allows an occupant of the wheelchair to operate the wheelchair by propelling himself with one arm by frictional engagement of the device with the surface in the front periphery of the wheelchair.
B. Description of the Prior Art
Conventional wheelchairs are operated manually by a ring attached to the rim of large wheels. This type of wheelchair, however, cannot be operated by someone who has limited use of one arm, such as someone who is paralyzed in one of their upper extremities. Unconventional wheelchairs designed for operation with one arm have been introduced. One such wheelchair comprises double rings on one side of the wheelchair whereby one ring operates the wheel on one side of the wheelchair and the other ring operate the wheel on the other side of the wheelchair, however with this chair, it is extremely difficult to maneuver sharp turns around items normally found in areas of their use. Another such wheelchair comprises a lever linked with a differential mechanism which through an expansion joint operates forward/backward clutches driven to interlock with the differential mechanism. This device is awkward to operate, limited in its use, expensive to manufacture and difficult to install. Even other wheelchairs have been introduced, but they are complicated, expensive, difficult to install and difficult or impossible to be operated with one arm.
Heretofore there has not been a device available that could be adapted to a powered wheelchair during the time it is disabled whereby the occupant can continue mobility. Such a device is especially needed for this application because occupants of powered wheelchairs are usually more disabled. It is therefore desired that there be a device which is simple, easy to use, inexpensive, adaptable to most wheelchairs and especially usable with one arm.
Examples of wheelchairs introduced in the art includes the following:
U.S. Pat. No. 4,506,900 to Koroosue discloses a "Lever-Operated Type of wheelchair" which utilizes the forward/backward clutches as described above.
U.S. Pat. No. 3,994,509, to Schaeffer discloses a "Propulsion Means for Wheelchairs" which comprises two drive assemblies mounted one on each side of a wheelchair, which means includes a lever pivotally mounted on and engaged with the axle of the wheelchair.
U.S. Pat. No. 4,538,826, to Lemarie disloses an "Aid for Propelling Wheeled Vehicles" by use of a pair of arms which operates caliper assemblies which engages and rotates the wheels through the operation of the arms.
U.S. Pat. No. 4,354,691, to Saunders et. al. discloses a "Wheel Chair Propulsion System" which utilizes an annular ring smaller than the diameter of the large wheel, which annular ring is engaged by a lever pivotally mounted on the axle of the large wheel.
U.S. Pat. No. 4,126,329, to Tehernyak discloses a "Wheeled Vehicle With Oar-Type propulsion" which utilizes levers which operates a drive mechanism including first and second drive wheels rotated by an oar-type motion of the levers.
U.S. Pat. No. 4,692,784, to Anderson discloses a "Wheelchair With Variable Ratio Propulsion" utilizing concentric ratchet rings operated by levers on the side of the wheelchair engagable with the ratchet rings.
U.S. Pat. No. 4,560,181, to Herron discloses a "Wheelchair Operated by Hand Pedalled Reciprocating Motion" which is powered by reciprocating operation of a drive lever which operates a drive mechanism having continuously variable gear ratios.
U.S. Pat. No. 4,762,332, to Seol discloses a "Wheel Chair" having a propulsion and speed change mechanism utilizing a clutch and a cam clutch.
U.S. Pat. No. 4,453,729, to Lucken discloses an "Occupant Propellable Wheelchair" utilizing reciprocating levers on each side of the wheelchair which drives the wheels by a rachet mechanism.